Aortic aneurysms and degeneration of the vasculature in general represent a significant medical problem for the general population. Aneurysms within the aorta presently affect between two and seven percent of the general population and the rate of incidence appears to be increasing. This form of vascular disease is characterized by degeneration in the arterial wall in which the wall weakens and balloons outward. Until the affected artery is grafted through open repair or treated with a stent graft endovascularly, a patient with an aortic aneurysm must live with the threat of aortic aneurysm rupture and death.
One known clinical approach for patients with an aortic aneurysm is a surgical repair procedure. This is an extensive operation involving dissection of the aorta and reinforcement of the aneurysm wall with a prosthetic graft.
Alternatively, there is a significantly less invasive clinical approach to aneurysm repair known as endovascular grafting. Endovascular grafting involves the placement of a prosthetic arterial stent graft within the lumen of the artery. To prevent rupture of the aneurysm, a stent graft of tubular construction is introduced into the blood vessel, and is secured in a location such that the stent graft spans the length of the aneurysmal sac. The outer surface of the stent graft at its ends is sealed to the interior wall of the blood vessel at a location where the blood vessel wall has not suffered a loss of strength or resiliency, such that blood flowing through the vessel is diverted through the hollow interior of the stent graft away from the blood vessel wall at the aneurysmal sac location. In this way, the risk of rupture of the blood vessel wall at the aneurysmal location is reduced significantly and blood can continue to flow through to the downstream blood vessels without interruption. However, despite the advantages of endovascular grafting over other surgical procedures, there may be, nonetheless, continued progression of the aneurysm.
A salient feature of aneurysm formation is the gradual degradation of extracellular components, such as collagen and elastin, as well as the loss of resident cells. The cells in a healthy vessel perform many and varied functions, including providing reinforcement to the vessel wall and, importantly, replenishing the extracellular components. The diminished cellular presence observed in diseased arteries directly and adversely impacts the vessel wall ultrastructure.
Thus there is a desire in the art to slow, reverse, or cure the aneurysm disease state by using minimally invasive procedures while reducing or eliminating immunological rejection.